import { Context } from '@deepseek-ai/cordis'
import SystemPrompt, { renderPrompt } from '@deepseek-ai/dsh-system-prompt'
import { createScope, type ScopeKey } from '@deepseek-ai/dsh-scope'
import { describe, expect, it } from 'vitest'
import * as Persona from '@deepseek-ai/dsh-persona'
import { PERSONA_SECTION } from '@deepseek-ai/dsh-persona'

async function harness(deploymentPersona: string): Promise<Context> {
  const ctx = new Context()
  await ctx.plugin(SystemPrompt, { persona: deploymentPersona })
  return ctx
}

/** The rendered text of the persona slot as one scope sees it. */
async function personaText(ctx: Context, scope?: ScopeKey): Promise<string | undefined> {
  const assembly = await ctx.systemPrompt.assemble(scope === undefined ? {} : { scope })
  return assembly.sections.find(section => section.name === PERSONA_SECTION)?.text
}

describe('the persona row', () => {
  it('rejects an unscoped mount, which would collide with the registry default', async () => {
    const ctx = await harness('deployment identity')

    await expect(ctx.plugin(Persona, { text: 'composition identity' }))
      .rejects.toThrow(/"deployment:persona" is already registered/)
  })

  it('shadows the deployment default for one scope only', async () => {
    const ctx = await harness('deployment identity')
    const key: ScopeKey = { agent: 'a1' }
    const scope = createScope(ctx, key)

    await scope.ctx.plugin(Persona, { text: 'preset identity' })

    expect(await personaText(ctx, key)).toBe('preset identity')
    expect(await personaText(ctx)).toBe('deployment identity')
  })

  it('gives two scopes independent personas', async () => {
    const ctx = await harness('')
    const first: ScopeKey = { agent: 'a1' }
    const second: ScopeKey = { agent: 'a2' }

    await createScope(ctx, first).ctx.plugin(Persona, { text: 'first identity' })
    await createScope(ctx, second).ctx.plugin(Persona, { text: 'second identity' })

    expect(await personaText(ctx, first)).toBe('first identity')
    expect(await personaText(ctx, second)).toBe('second identity')
  })

  it('shadows the deployment persona away entirely when its text is empty', async () => {
    const ctx = await harness('deployment identity')
    const key: ScopeKey = { agent: 'a1' }

    await createScope(ctx, key).ctx.plugin(Persona, { text: '' })

    // The slot is still occupied, so the deployment persona is gone for this
    // agent; an empty section is dropped when the prompt renders.
    expect(await personaText(ctx, key)).toBe('')
    expect(await personaText(ctx)).toBe('deployment identity')
  })

  it('restores the shadowed default when its fiber unloads', async () => {
    const ctx = await harness('deployment identity')
    const key: ScopeKey = { agent: 'a1' }
    const scope = createScope(ctx, key)
    const fiber = await scope.ctx.plugin(Persona, { text: 'preset identity' })
    expect(await personaText(ctx, key)).toBe('preset identity')

    await fiber.dispose()

    expect(await personaText(ctx, key)).toBe('deployment identity')
  })

  it('interpolates prompt variables strictly, like any other section', async () => {
    const ctx = await harness('')
    const key: ScopeKey = { agent: 'a1' }
    ctx.systemPrompt.variable('model', () => 'deepseek-v4-pro')

    await createScope(ctx, key).ctx.plugin(Persona, { text: 'You run on {{model}}.' })

    // `assemble()` keeps section text uninterpolated; `renderPrompt()` is the
    // stage that resolves `{{…}}` against the assembly's variables.
    expect(await personaText(ctx, key)).toBe('You run on {{model}}.')
    expect(renderPrompt(await ctx.systemPrompt.assemble({ scope: key })))
      .toContain('You run on deepseek-v4-pro.')
  })

  it('makes a complete persona the exact prompt after every other contribution', async () => {
    const ctx = await harness('deployment identity')
    const key: ScopeKey = { agent: 'a1' }
    const scope = createScope(ctx, key)
    ctx.systemPrompt.section({ name: 'global:extra', order: 100, text: 'global guidance' })

    await scope.ctx.plugin(Persona, { text: 'Only this.', complete: true })
    scope.ctx.on('system-prompt/assemble', async (assembly, _context, next) => {
      assembly.sections.push({ name: 'late:extra', text: 'late guidance' })
      return next()
    }, { prepend: true })

    const assembly = await ctx.systemPrompt.assemble({ scope: key })
    expect(assembly.sections).toEqual([{ name: PERSONA_SECTION, text: 'Only this.' }])
    expect(renderPrompt(assembly)).toBe('Only this.')
  })

  it('can suppress runtime context for its scope without changing the global assembly', async () => {
    const ctx = await harness('deployment identity')
    const key: ScopeKey = { agent: 'a1' }
    const scope = createScope(ctx, key)
    ctx.systemPrompt.context({ name: 'policy', order: 1, text: 'global policy' })

    const fiber = await scope.ctx.plugin(Persona, {
      text: 'Only this.',
      includeRuntimeContext: false,
    })
    const suppressed = await ctx.systemPrompt.assemble({ scope: key })
    expect(suppressed.contexts).toEqual([])
    const global = await ctx.systemPrompt.assemble()
    expect(global.contexts).toEqual([
      { name: 'policy', text: 'global policy' },
    ])

    await fiber.dispose()
    expect((await ctx.systemPrompt.assemble({ scope: key })).contexts).toEqual([
      { name: 'policy', text: 'global policy' },
    ])
  })

  it('keeps runtime context by default when apply bypasses schema defaults', async () => {
    const ctx = await harness('deployment identity')
    const key: ScopeKey = { agent: 'a1' }
    ctx.systemPrompt.context({ name: 'policy', order: 1, text: 'global policy' })

    await ctx.plugin(Object.assign((inner: Context) => {
      Persona.apply(createScope(inner, key).ctx, { text: 'Scoped identity.' })
    }, { inject: ['systemPrompt'] }))

    expect((await ctx.systemPrompt.assemble({ scope: key })).contexts).toEqual([
      { name: 'policy', text: 'global policy' },
    ])
  })
})