package herdr

import (
	"context"
	"fmt"
	"time"
)

type Adapter interface {
	Lease(context.Context, string, string) (Session, error)
	Bootstrap(context.Context, Session, string) error
	Release(context.Context, Session) (string, error)
	Kill(context.Context, Session) error
	Occupancy(Session) (float64, error)
}

// TurnBoundary is optional so older herdr deployments remain usable. A true
// result means the current harness turn has ended and handoff is safe.
type TurnBoundary interface {
	AtTurnBoundary(context.Context, Session) (bool, error)
}
type RotationSignal interface {
	RotationSignal(context.Context, Session) (string, error)
}
type CLIAdapter struct {
	Client  *Client
	Harness string
	Window  int64
	Usage   func(string) (Usage, error)
}

func (a CLIAdapter) Lease(ctx context.Context, task, worktree string) (Session, error) {
	if a.Client == nil {
		return Session{}, fmt.Errorf("adapter: client required")
	}
	var s Session
	e := a.Client.Call(ctx, "pane.create", map[string]string{"harness": a.Harness, "task_id": task, "worktree": worktree}, &s)
	s.Harness = a.Harness
	s.Worktree = worktree
	return s, e
}
func (a CLIAdapter) Bootstrap(ctx context.Context, s Session, ref string) error {
	return a.Client.Prompt(ctx, s.PaneID, fmt.Sprintf("Read handoff %s, validate the anchor and TASK.md, then continue.", ref), time.Minute)
}
func (a CLIAdapter) Release(ctx context.Context, s Session) (string, error) {
	var r struct {
		Ref string `json:"handoff_ref"`
	}
	e := a.Client.Call(ctx, "pane.release", s, &r)
	return r.Ref, e
}
func (a CLIAdapter) Kill(ctx context.Context, s Session) error {
	return a.Client.Call(ctx, "pane.kill", s, nil)
}
func (a CLIAdapter) AtTurnBoundary(ctx context.Context, s Session) (bool, error) {
	var r struct {
		Status string `json:"status"`
	}
	if err := a.Client.Call(ctx, "pane.status", s, &r); err != nil {
		return false, err
	}
	return !IsBusy(r.Status), nil
}
func (a CLIAdapter) RotationSignal(ctx context.Context, s Session) (string, error) {
	var r struct {
		Reason string `json:"reason"`
	}
	if err := a.Client.Call(ctx, "pane.rotation_signal", s, &r); err != nil {
		return "", err
	}
	return r.Reason, nil
}
func (a CLIAdapter) Occupancy(s Session) (float64, error) {
	if a.Usage == nil {
		return 0, fmt.Errorf("adapter: usage reader required")
	}
	u, e := a.Usage(s.PaneID)
	return Fraction(u, a.Window), e
}

var Claude = func(c *Client, w int64) CLIAdapter {
	return CLIAdapter{Client: c, Harness: "claude", Window: w, Usage: ClaudeUsage}
}
var Codex = func(c *Client, w int64) CLIAdapter {
	return CLIAdapter{Client: c, Harness: "codex", Window: w, Usage: CodexUsage}
}
var OpenCode = func(c *Client, w int64) CLIAdapter {
	return CLIAdapter{Client: c, Harness: "opencode", Window: w, Usage: OpenCodeUsage}
}