package tasksboard

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"strings"
	"time"
)

type Client struct {
	BaseURL    string
	Token      string
	HTTPClient *http.Client
}

func (c *Client) http() *http.Client {
	if c.HTTPClient != nil {
		return c.HTTPClient
	}
	return http.DefaultClient
}

type Task struct {
	ID          string `json:"id"`
	Title       string `json:"title"`
	Description string `json:"description"`
	Status      string `json:"status"`
	Priority    int    `json:"priority"`
	Project     *struct {
		ID   string `json:"id"`
		Slug string `json:"slug"`
		Name string `json:"name"`
	} `json:"project,omitempty"`
	Assignee *struct {
		Type        string `json:"type"`
		ID          string `json:"id"`
		DisplayName string `json:"display_name,omitempty"`
	} `json:"assignee,omitempty"`
}

type Comment struct {
	ID         string    `json:"id"`
	TaskID     string    `json:"task_id"`
	AuthorType string    `json:"author_type"`
	AuthorID   string    `json:"author_id"`
	Body       string    `json:"body"`
	CreatedAt  time.Time `json:"created_at"`
}

func (c *Client) GetTask(ctx context.Context, taskID string) (Task, error) {
	var t Task
	if err := c.doJSON(ctx, http.MethodGet, "/api/v1/tasks/"+url.PathEscape(taskID), "", nil, &t); err != nil {
		return Task{}, err
	}
	return t, nil
}

func (c *Client) ListComments(ctx context.Context, taskID string) ([]Comment, error) {
	var out struct {
		Comments []Comment `json:"comments"`
	}
	if err := c.doJSON(ctx, http.MethodGet, "/api/v1/tasks/"+url.PathEscape(taskID)+"/comments", "", nil, &out); err != nil {
		return nil, err
	}
	return out.Comments, nil
}

func (c *Client) PostComment(ctx context.Context, taskID, body, idempotencyKey string) (Comment, error) {
	var out Comment
	payload := map[string]string{"body": body}
	if err := c.doJSON(ctx, http.MethodPost, "/api/v1/tasks/"+url.PathEscape(taskID)+"/comments", idempotencyKey, payload, &out); err != nil {
		return Comment{}, err
	}
	return out, nil
}

func (c *Client) doJSON(ctx context.Context, method, path, idempotencyKey string, body any, dst any) error {
	base := strings.TrimRight(c.BaseURL, "/")
	var rdr io.Reader
	if body != nil {
		b, err := json.Marshal(body)
		if err != nil {
			return err
		}
		rdr = bytes.NewReader(b)
	}
	req, err := http.NewRequestWithContext(ctx, method, base+path, rdr)
	if err != nil {
		return err
	}
	req.Header.Set("Authorization", "Bearer "+c.Token)
	if body != nil {
		req.Header.Set("Content-Type", "application/json")
	}
	if idempotencyKey != "" {
		req.Header.Set("Idempotency-Key", idempotencyKey)
	}
	resp, err := c.http().Do(req)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	data, err := io.ReadAll(io.LimitReader(resp.Body, 1<<20))
	if err != nil {
		return err
	}
	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		return fmt.Errorf("tasks %s %s: status %d: %s", method, path, resp.StatusCode, strings.TrimSpace(string(data)))
	}
	if dst == nil || len(data) == 0 {
		return nil
	}
	return json.Unmarshal(data, dst)
}