const std = @import("std");

const builtin = @import("builtin");

const helper = @import("helper.zig");
const Data = @import("Data.zig");
const Parsed = @import("Parsed.zig");
const Log = @import("Log.zig");

pub const Status = enum(c_int) {
    unchanged = 0,
    created,
    deleted,
    modified,
};

pub const Change = struct {
    status: Status, // never .unchanged
    id: Data.Id,

    source: ?[]const u8 = null,
    output: ?[]const u8 = null,

    title: ?[]const u8 = null,
    description: ?[]const u8 = null,
    author: ?[]const u8 = null,

    timestamp: i64,

    pub fn copy(self: Change, allocator: std.mem.Allocator) !Change {
        return Change{
            .status = self.status,
            .id = self.id,

            .source = if (self.source) |src|
                try allocator.dupe(u8, src)
            else
                null,

            .output = if (self.output) |output|
                try allocator.dupe(u8, output)
            else
                null,

            .title = if (self.title) |title|
                try allocator.dupe(u8, title)
            else
                null,

            .description = if (self.description) |description|
                try allocator.dupe(u8, description)
            else
                null,

            .author = if (self.author) |author|
                try allocator.dupe(u8, author)
            else
                null,

            .timestamp = self.timestamp,
        };
    }

    pub fn deinit(self: Change, allocator: std.mem.Allocator) void {
        if (self.source) |src| allocator.free(src);
        if (self.output) |output| allocator.free(output);
        if (self.title) |title| allocator.free(title);
        if (self.description) |description| allocator.free(description);
        if (self.author) |author| allocator.free(author);
    }
};

on_change: ?[]const u8 = null,
on_create: ?[]const u8 = null,
on_delete: ?[]const u8 = null,
on_modify: ?[]const u8 = null,

const Callbacks = @This();

fn callSystemProgram(
    program: []const u8,
    stdin_input: []const u8,
    cwd: std.fs.Dir,
    allocator: std.mem.Allocator,
) !void {
    var args = std.ArrayList([]const u8).init(allocator);
    defer args.deinit();

    if (builtin.os.tag == .windows) {
        try args.append("cmd.exe");
        try args.append("/C");
    } else {
        try args.append("/bin/sh");
        try args.append("-c");
    }
    try args.append(program);

    var child = std.process.Child.init(args.items, allocator);

    child.cwd_dir = cwd;

    child.stdin_behavior = .Pipe;
    child.stdout_behavior = .Ignore;
    child.stderr_behavior = .Inherit;

    var env_map = std.process.EnvMap.init(allocator);
    defer env_map.deinit();

    try env_map.put("FROM_MAKKO", "YES");

    child.env_map = &env_map;

    try child.spawn();

    if (child.stdin) |stdin| {
        _ = try stdin.writeAll(stdin_input);
        stdin.close();
        child.stdin = null;
    }

    _ = try child.wait();
}

fn lessThan(context: void, a: Change, b: Change) bool {
    _ = context;
    return @intFromEnum(a.status) < @intFromEnum(b.status);
}

pub fn run(
    callbacks: Callbacks,
    changes: []Change,
    cwd: std.fs.Dir,
    log: Log,
    allocator: std.mem.Allocator,
) !void {
    if (changes.len == 0)
        return;

    //std.sort.block(Change, changes, {}, lessThan);

    var created_changes = std.ArrayList(Change).init(allocator);
    var deleted_changes = std.ArrayList(Change).init(allocator);
    var modified_changes = std.ArrayList(Change).init(allocator);

    defer {
        created_changes.deinit();
        deleted_changes.deinit();
        modified_changes.deinit();
    }

    for (changes) |change| {
        switch (change.status) {
            .created => try created_changes.append(change),
            .deleted => try deleted_changes.append(change),
            .modified => try modified_changes.append(change),

            .unchanged => {},
        }
    }

    if ((created_changes.items.len > 0 and callbacks.on_create != null) or
        (deleted_changes.items.len > 0 and callbacks.on_delete != null) or
        (modified_changes.items.len > 0 and callbacks.on_modify != null) or
        callbacks.on_change != null)
        log.header("Callbacks");

    if (callbacks.on_change) |on_change| {
        const json = try std.json.stringifyAlloc(
            allocator,
            changes,
            .{},
        );
        defer allocator.free(json);

        log.raw("- on_change: {s}\n", .{on_change});
        try callSystemProgram(on_change, json, cwd, allocator);
    }

    if (callbacks.on_create) |on_create| {
        if (created_changes.items.len > 0) {
            const json = try std.json.stringifyAlloc(
                allocator,
                created_changes.items,
                .{},
            );
            defer allocator.free(json);

            log.raw("- on_create: {s}\n", .{on_create});
            try callSystemProgram(on_create, json, cwd, allocator);
        }
    }

    if (callbacks.on_delete) |on_delete| {
        if (deleted_changes.items.len > 0) {
            const json = try std.json.stringifyAlloc(
                allocator,
                deleted_changes.items,
                .{},
            );
            defer allocator.free(json);

            log.raw("- on_delete: {s}\n", .{on_delete});
            try callSystemProgram(on_delete, json, cwd, allocator);
        }
    }

    if (callbacks.on_modify) |on_modify| {
        if (modified_changes.items.len > 0) {
            const json = try std.json.stringifyAlloc(
                allocator,
                modified_changes.items,
                .{},
            );
            defer allocator.free(json);

            log.raw("- on_modify: {s}\n", .{on_modify});
            try callSystemProgram(on_modify, json, cwd, allocator);
        }
    }
}