import * as z from "zod";
import { Id } from "./ids.js";
import { MediaFitSchema, MediaPresetIdSchema } from "./media.js";

/**
 * Inputs of the `edit_video` and `export_video` media operations, which are also the arguments
 * of the tools with those names. Times are seconds on the timeline left by the previous steps.
 */

const Seconds = z.number().min(0).max(86_400);

const TimeRangeSchema = z
  .object({ start: Seconds, end: Seconds })
  .refine((range) => range.end > range.start, "end must be after start");

/** Written by the bot in the user's language; shown on the media card and used as file name. */
export const MediaTitleSchema = z.string().trim().min(1).max(120);

export const EditVideoStepSchema = z.discriminatedUnion("op", [
  z
    .object({ op: z.literal("trim"), start: Seconds, end: Seconds })
    .refine((step) => step.end > step.start, "end must be after start"),
  /** Keeps these parts and cuts everything between them. */
  z.object({ op: z.literal("keep"), segments: z.array(TimeRangeSchema).min(1).max(50) }),
  /** Appends these videos, fitted to the current frame. */
  z.object({ op: z.literal("concat"), artifact_ids: z.array(Id).min(1).max(20) }),
  z.object({
    op: z.literal("reframe"),
    preset: MediaPresetIdSchema,
    fit: MediaFitSchema.default("crop"),
  }),
  z.object({ op: z.literal("speed"), factor: z.number().min(0.25).max(4) }),
  /** Linear gain: 0.5 halves the loudness, 2 doubles it. */
  z.object({ op: z.literal("volume"), gain: z.number().min(0).max(8) }),
  z.object({ op: z.literal("mute") }),
  /** Burns in an SRT or VTT artifact. */
  z.object({ op: z.literal("subtitles"), artifact_id: Id }),
  /** Last step only: the result is the audio as M4A. */
  z.object({ op: z.literal("extract_audio") }),
  /** Cover frame at this second of the result; as the only kind of step, the result is that image. */
  z.object({ op: z.literal("poster"), at: Seconds }),
]);
export type EditVideoStep = z.infer<typeof EditVideoStepSchema>;

export const EditVideoInputSchema = z
  .object({
    artifact_id: Id,
    steps: z.array(EditVideoStepSchema).min(1).max(20),
    title: MediaTitleSchema,
  })
  .superRefine((input, context) => {
    const ops = input.steps.map((step) => step.op);
    const extract = ops.indexOf("extract_audio");
    if (extract >= 0 && extract !== ops.length - 1) {
      context.addIssue({
        code: "custom",
        path: ["steps", extract],
        message: "extract_audio must be the last step",
      });
    }
    if (extract >= 0 && ops.includes("poster")) {
      context.addIssue({
        code: "custom",
        path: ["steps"],
        message: "poster cannot be combined with extract_audio",
      });
    }
    if (ops.filter((op) => op === "poster").length > 1) {
      context.addIssue({ code: "custom", path: ["steps"], message: "use at most one poster step" });
    }
  });
export type EditVideoInput = z.infer<typeof EditVideoInputSchema>;

export const ExportVideoInputSchema = z.object({
  artifact_id: Id,
  presets: z.array(MediaPresetIdSchema).min(1).max(6),
  fit: MediaFitSchema.default("crop"),
  title: MediaTitleSchema.optional(),
});
export type ExportVideoInput = z.infer<typeof ExportVideoInputSchema>;