const std = @import("std");
const lang = @import("lang.zig");
const images = @import("image.zig");
const plugin = @import("plugin.zig");
const custom = @import("custom.zig");
const magick = @import("magick.zig");

const log = std.log.scoped(.scritcher_runner);

const Position = plugin.Position;
const ParamList = plugin.ParamList;
const ParamMap = plugin.ParamMap;

const Image = images.Image;

pub const RunError = error{
    UnknownCommand,
    NoBMP,
    ImageRequired,
};

pub const Runner = struct {
    allocator: std.mem.Allocator,

    /// The currently opened image in the runner
    image: ?*Image = null,

    /// If the runner is in REPL mode
    repl: bool,

    args: []const [:0]u8,

    pub fn init(allocator: std.mem.Allocator, repl: bool) Runner {
        return Runner{
            .allocator = allocator,
            .repl = repl,
            .args = std.process.argsAlloc(allocator) catch unreachable,
        };
    }

    pub fn deinit(self: *Runner) void {
        if (self.image) |image| {
            image.close();
        }

        std.process.argsFree(self.allocator, self.args);
    }

    pub fn clone(self: *Runner) !Runner {
        var cloned_image = if (self.image) |image| try image.clone() else null;
        return Runner{
            .allocator = self.allocator,
            .image = cloned_image,
            .repl = self.repl,
            .args = self.args,
        };
    }

    fn resolveArg(self: *Runner, load_path: []const u8) ![]const u8 {
        std.debug.assert(load_path.len > 0);
        if (load_path[0] == ':') {
            // parse the index from 1 to end
            var index = try std.fmt.parseInt(usize, load_path[1..], 10);

            // if it isn't in the repl, args look like this:
            // 'scritcher ./script ./image'
            // if it is, it looks like this
            // 'scritcher repl ./script ./image'

            // ':0' should ALWAYS point to the image.
            if (self.repl) index += 3 else index += 3;

            for (self.args) |arg, idx| {
                log.debug("arg{d} = {s}\n", .{ idx, arg });
            }
            log.debug("fetch arg idx={d}, val={s}\n", .{ index, self.args[index] });
            return self.args[index];
        } else {
            return load_path;
        }
    }

    // Caller owns returned memory.
    fn resolveArgPath(self: *Runner, path_or_argidx: []const u8) ![]const u8 {
        const path = try self.resolveArg(path_or_argidx);
        const resolved_path = try std.fs.path.resolve(
            self.allocator,
            &[_][]const u8{path},
        );

        return resolved_path;
    }

    fn loadCmd(self: *Runner, path_or_argidx: []const u8) !void {
        const load_path = try self.resolveArgPath(path_or_argidx);
        log.debug("\tload path: {s}\n", .{load_path});

        // we could use ImageMagick to convert from X to BMP
        // but i can't find an easy way to do things in memory.

        // the upside is that this allows some pre-processing by the user
        // before loading the file into scritcher. for example, you can start
        // krita/gimp and make it export a bmp and while in the program you can
        // apply filters, etc.
        if (!std.mem.endsWith(u8, load_path, ".bmp") and !std.mem.endsWith(u8, load_path, ".ppm")) {
            log.debug("Only BMP files are allowed to be loaded. Got path '{s}'\n", .{load_path});
            return RunError.NoBMP;
        }

        // we don't copy load_path into a temporary file because we're already
        // loading it under the SFM_READ mode, which won't cause any destructive
        // operations on the file.
        if (self.image) |image| image.close();
        self.image = try Image.open(self.allocator, load_path);
    }

    fn getImage(self: *Runner) !*Image {
        if (self.image) |image| {
            return image;
        } else {
            log.debug("image is required!\n", .{});
            return RunError.ImageRequired;
        }
    }

    /// Caller owns returned memory.
    fn makeGlitchedPath(self: *Runner) ![]const u8 {
        // we want to transform basename, if it is "x.bmp" to "x_gN.bmp", where
        // N is the maximum non-used integer.
        var image = try self.getImage();

        const basename = std.fs.path.basename(image.path);
        const dirname = std.fs.path.dirname(image.path).?;

        var dir = try std.fs.cwd().openIterableDir(dirname, .{});
        defer dir.close();

        const period_idx = std.mem.lastIndexOf(u8, basename, ".").?;
        const extension = basename[period_idx..basename.len];

        // starts_with would be "x_g", we want to find all files in the directory
        // that start with that name.
        const starts_with = try std.fmt.allocPrint(self.allocator, "{s}_g", .{
            basename[0..period_idx],
        });
        defer self.allocator.free(starts_with);

        var max: usize = 0;

        var it = dir.iterate();

        while (try it.next()) |entry| {
            switch (entry.kind) {
                .File => blk: {
                    if (!std.mem.startsWith(u8, entry.name, starts_with)) break :blk {};

                    // we want to get the N in x_gN.ext
                    const entry_gidx = std.mem.lastIndexOf(u8, entry.name, "_g").?;

                    const entry_pidx_opt = std.mem.lastIndexOf(u8, entry.name, ".");
                    if (entry_pidx_opt == null) break :blk {};

                    const entry_pidx = entry_pidx_opt.?;

                    // if N isn't a number, we just ignore that file
                    const idx_str = entry.name[entry_gidx + 2 .. entry_pidx];
                    const idx = std.fmt.parseInt(usize, idx_str, 10) catch |err| {
                        log.debug("ignoring file {s}", .{@errorName(err)});

                        break :blk {};
                    };

                    if (idx > max) max = idx;
                },
                else => {},
            }
        }

        const out_path = try std.fmt.allocPrint(self.allocator, "{s}/{s}{d}{s}", .{
            dirname,
            starts_with,
            max + 1,
            extension,
        });

        return out_path;
    }

    fn quicksaveCmd(self: *Runner) !void {
        var image = try self.getImage();
        const out_path = try self.makeGlitchedPath();
        defer self.allocator.free(out_path);
        try image.saveTo(out_path);
    }

    fn runQSCmd(self: *Runner, cmd: lang.Command) !void {
        const runqs = cmd.cast(lang.Command.RunQS).?;
        var image = try self.getImage();
        const out_path = try self.makeGlitchedPath();
        defer self.allocator.free(out_path);
        try image.saveTo(out_path);

        var proc = std.ChildProcess.init(
            &[_][]const u8{ runqs.program, out_path },
            self.allocator,
        );
        //defer proc.deinit();

        log.debug("running '{s} {s}'\n", .{ runqs.program, out_path });
        _ = try proc.spawnAndWait();
    }

    fn rotateCmd(self: *Runner, cmd: lang.Command) !void {
        const rotate_cmd = cmd.cast(lang.Command.Rotate).?;

        var image = try self.getImage();
        var c_bgfill = try std.cstr.addNullByte(self.allocator, rotate_cmd.bgfill);
        defer self.allocator.free(c_bgfill);

        try magick.runRotate(image, rotate_cmd.deg, c_bgfill);
    }

    fn executeLV2Command(self: *@This(), command: anytype) !void {
        const pos = plugin.Position{
            .split = command.split,
            .index = command.index,
        };

        var params = ParamList.init(self.allocator);
        defer params.deinit();

        const typ = @TypeOf(command);

        inline for (@typeInfo(@TypeOf(command.parameters)).Struct.fields) |cmd_field| {
            try params.append(plugin.Param{
                .sym = cmd_field.name,
                .value = @field(command.parameters, cmd_field.name),
            });
        }

        var image = try self.getImage();
        try image.runPlugin(typ.lv2_url, pos, params);
    }

    fn executeCustomCommand(self: *@This(), command: anytype) !void {
        const pos = plugin.Position{
            .split = command.split,
            .index = command.index,
        };

        var image = try self.getImage();
        try image.runCustomPlugin(@TypeOf(command).plugin_type, pos, command.parameters);
    }

    fn runSingleCommand(
        self: *@This(),
        cmd: lang.Command,
        comptime tag: lang.Command.Tag,
    ) !void {
        const typ = lang.Command.tagToType(tag);
        const command = cmd.cast(typ).?;
        const ctype = typ.command_type;
        switch (ctype) {
            .lv2_command => try self.executeLV2Command(command.*),
            .custom_command => try self.executeCustomCommand(command.*),
        }
    }

    fn runCommand(self: *@This(), cmd: lang.Command) !void {
        switch (cmd.tag) {
            .noop => {},
            .load => {
                const command = cmd.cast(lang.Command.Load).?;
                try self.loadCmd(command.path);
            },
            .quicksave => try self.quicksaveCmd(),
            .rotate => try self.rotateCmd(cmd),
            .runqs => try self.runQSCmd(cmd),

            .amp => try self.runSingleCommand(cmd, .amp),
            .rflanger => try self.runSingleCommand(cmd, .rflanger),
            .eq => try self.runSingleCommand(cmd, .eq),
            .phaser => try self.runSingleCommand(cmd, .phaser),
            .mbeq => try self.runSingleCommand(cmd, .mbeq),
            .chorus => try self.runSingleCommand(cmd, .chorus),
            .pitchscaler => try self.runSingleCommand(cmd, .pitchscaler),
            .reverb => try self.runSingleCommand(cmd, .reverb),
            .highpass => try self.runSingleCommand(cmd, .highpass),
            .delay => try self.runSingleCommand(cmd, .delay),
            .vinyl => try self.runSingleCommand(cmd, .vinyl),
            .revdelay => try self.runSingleCommand(cmd, .revdelay),
            .gate => try self.runSingleCommand(cmd, .gate),
            .detune => try self.runSingleCommand(cmd, .detune),
            .overdrive => try self.runSingleCommand(cmd, .overdrive),
            .degrade => try self.runSingleCommand(cmd, .degrade),
            .repsycho => try self.runSingleCommand(cmd, .repsycho),
            .talkbox => try self.runSingleCommand(cmd, .talkbox),
            .dyncomp => try self.runSingleCommand(cmd, .dyncomp),
            .thruzero => try self.runSingleCommand(cmd, .thruzero),
            .foverdrive => try self.runSingleCommand(cmd, .foverdrive),
            .gverb => try self.runSingleCommand(cmd, .gverb),
            .invert => try self.runSingleCommand(cmd, .invert),
            .tapedelay => try self.runSingleCommand(cmd, .tapedelay),
            .moddelay => try self.runSingleCommand(cmd, .moddelay),
            .multichorus => try self.runSingleCommand(cmd, .multichorus),
            .saturator => try self.runSingleCommand(cmd, .saturator),
            .vintagedelay => try self.runSingleCommand(cmd, .vintagedelay),

            .noise => try self.runSingleCommand(cmd, .noise),
            .wildnoise => try self.runSingleCommand(cmd, .wildnoise),
            .write => try self.runSingleCommand(cmd, .write),
            .embed => try self.runSingleCommand(cmd, .embed),
        }
    }
    /// Run a list of commands.
    pub fn runCommands(
        self: *Runner,
        cmds: lang.CommandList,
        debug_flag: bool,
    ) !void {
        _ = debug_flag;
        for (cmds.list.items) |cmd| {
            cmd.print();
            try self.runCommand(cmd.*);
        }
    }
};

test "running noop" {
    const allocator = std.testing.allocator;
    var cmds = lang.CommandList.init(allocator);
    defer cmds.deinit();

    var command = lang.Command{ .tag = .noop };

    var noop = try allocator.create(lang.Command.Noop);
    noop.* = lang.Command.Noop{ .base = command };
    try cmds.append(&noop.base);

    var runner = Runner.init(allocator, false);
    defer runner.deinit();

    try runner.runCommands(cmds, false);
}